Abstract
ABSTRACT This study evaluated soft-bodied benthic algae from seven streams located in protected areas of central Brazil (Parque Nacional de Brasilia, Parque Nacional da Chapada dos Veadeiros and Parque Estadual de Terra Ronca), and related them to abiotic factors. We addressed the following questions: A) how algal community structure in Cerrado streams is influenced by the marked seasonality typical of the region; and B) how karst geology influences algal communities in Parque Estadual de Terra Ronca, as compared to streams in other Cerrado areas. Samples were collected between 2012 and 2013 from a single site in each stream, and upstream and downstream of caves present in Parque Estadual de Terra Ronca. Altogether, 159 taxa were recorded. Algal community structure varied significantly among sites, but not between seasons, despite relatively lower abundances during the rainy season, likely due to a negative influence of the faster currents in streams during this period. Some alkaliphilic species were observed only at sites near caves (e.g. the cyanobacterium Tolypothrix distorta), while acidophilic taxa were more frequent in the other streams (e.g. desmids and Cyanobacteria such as Scytonema caldarium, Hapalosiphon stuhlmannii and Stigonema ocellatum). We observed a rare green alga, Microthamnion kuetzingianum, and reported the cyanobacterium Rivularia aquatica for the first time in Brazil.
Highlights
All over the world, anthropogenic influence on natural environments is increasing, and pristine aquatic systems are becoming scarce (Lindstrøm et al 2004)
This study evaluated soft-bodied benthic algae from seven streams located in protected areas of central Brazil (Parque Nacional de Brasília, Parque Nacional da Chapada dos Veadeiros and Parque Estadual de Terra Ronca), and related them to abiotic factors
The main environmental gradient was represented by spatial differences among the protected areas, with samples from PETeR associated with lower nutrient concentrations and higher temperature
Summary
Anthropogenic influence on natural environments is increasing, and pristine aquatic systems are becoming scarce (Lindstrøm et al 2004). Soft-bodied benthic (SB) algae have been defined as non-diatom algae, including cyanobacteria, attached to substrata in lotic environments (Rott & Schneider 2014). Studies on SB algae in reference conditions have been mainly carried out in streams from temperate regions of North America (Thomas et al 2015; Stancheva & Sheath 2016) and northern Europe (Lindstrøm et al 2004). In Brazil, this terminology has not been widely used; instead, the literature about benthic or periphytic algae in lotic systems mostly refers to diatoms Microscopic attached algae from other taxonomical groups are less known, which may lead to underestimated numbers for general phycological diversity in such environments
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